Sheet-feeding machine.



C. W. KRUEGEB.

SHEET FEEDING MACHINE.

APPLICATION HLED SEPT. 12. 1911.

Patented Dec. 18, 1917.

mvsui-ons OFFICE.

GARE: "W. munenn, OF 'MTLWAJUKEE, WISCONSIN, ASSIGNUR T NATIONAL PAPER CAN GOMPAlW, 0F MILWAUKEE, WISCONSI1\T, A CORPORATION OF DELAWARE.

SHEET-FEEDING MACHINE.

menace.

0 all whom may concern:

Be it known that I, CARL W. Knunenn, a

waukee, in the county of Milwaukee and State 'of Wisconsin, have invented anew and useful Improvement in Sheet-Feeding Machines, of which the following is a full, clear, and exact description, reference being had to the accom anying drawings, forming part of this speci cation, in which- Figure 1 is a side elevation. Fig. 2 is a side elevation showing the vacuum foot liftin and delivering the top sheet to the feed rol s. r

Fig. 3 is a longitudinal vertical section through the vacuum foot.

Fig. l is a bottom plan view of the foot, and

- Fig. 5 is a bottom plan view of the foot illustrating a modification.

My invention relates to sheet feeding machines and more particularly to sheet feedin machines in which a vacuum foot or ii er is employed to separate a single sheet from a pile of sheets.

Such machines are commonly used for feeding sheets of paper singly to printing, winding or other mechanisms.

The object of my invention is to provide a sheet feeding machine of this type in which the separation of-the top sheet from the pile is rendered more-certain.

In the embodiment of the invention illustrated in the drawings, a pile of pager sheets 2 is shown carried on a table 3. vacuum sheet lifting foot 4 is arranged to lift a single sheet from the top of the pile and transfer it to feed rolls 5, which in turn deliver it to a machine which is to operate upon the sheet. The vacuum foot 4 is lowered against the top of the pile of sheets, and the vacuum applied to the air passages in the foot which serves to draw the paper against the bottom of the foot. Then the foot is raised vertically from the position shown in Fig. 1 and thereafter moved horizontally forward to the position shown in Fig. 2 to deliver the forward end of the sheet to the feed rolls 5. Then the vacuum is released and the foot is returned to the top of the pile of sheets 2 and the operation repeated.

In the operations of machines of this charactor as heretofore constructed with a flat faced vacuum foot, considerable difliculty Specification of Letters Patent.

Fatented Dec. 18, 1917.

Application filed September 12, 1917. Serial No. 190,926.

has been encountered in picking u but a slngle sheet from the top of the pi e. The sheets tend to adhere together, particularly at the edges thereof, as the pile of sheets is frequently made by cutting up a pile of larger sheets into sheets of the requisite size.

The shearing tends to mat or mingle the fibers at the cut edges of the pile, so that when the top sheet'is lifted its out edges tend to raise with it the cut'edges of the sheets immediately beneath. Also, since the paper 1s more or less porous, the suction exerted by the vacuum foot tends 'to act through the to sheet and to draw the next sheet against t e foot. The present invention relates particularly to the shape of the sheet engaging face of the vacuum foot whereby its operation in picking up a single sheet from the pile is rendered more certain.

As shown in the drawings, the vacuum foot 4 is elongated and is provided with an air inlet in its lower face. As shown in Figs. 3 and 4 the air inlet is made up of a plurality of openings or mouths 6.

As shown in Fig. 5, the air inlet is formed by a continuous narrow slot or mouth 7. The air inlet communicates through the air passage 8 to a vacuum pump (not shown). The lower or sheet engaging face of the foot 4: is upwardly inclined or curved atboth ends, as-sho-wn in Fig. 3.

When the vacuum foot is placed on the top of the pile, of sheets, as shown in Fig. 1, and the vacuum is applied, the paper is drawn or sucked against the air inlet. The paper is first drawn against the openings, which as shown in Fig. 3, are at the flat or middle'part of, the foot, sealing these openings and limiting the intake to the months along the curved portion of the foot. The paper sheet is progressively lifted, the lowest mouths in the curved part next being sealed by the paper and so on until the edge of the paper is raised to seal the mouths at the highest part of the foot or nearest the edge of the paper.

By the progressive lifting of the sheet the comparatively long lift between the mouth at the extreme end of the foot and the edge of the aper is easily accomplished. The effect of the curved sheet against the curved bottom on the vacuum foot is usually to separate the edge of the top sheet from the sheet immediately below. The bending of the top sheet causes a fanning or slipping of the edges of the paper, which in case the edges of the paper are sheared and matted together, serves to pull them apart. The natural elasticity of the next sheet tends to hold it flat and pull its edge away from the curled-up edge of the top sheet.

Moreover, the curling up of the edge of the sheet as shown in Fig. 3, gives a free inlet for air between the to sheet and the sheet immediately below an tends to prevent the suction of the foot from acting on the second sheet. As above pointed out, the paper is more or less porous, and the suction tends to act through the top sheet upon the sheets immediately beneath and to draw them against the foot. The separation of the top sheet from the second sheet as shown in Fig. 3 permits air to enter between the sheets and breaks any vacuum which might act through the first sheet upon the second sheet so that when the foot is lifted the second sheet remains on the pile.

For convenience in construction, the air inlet in the bottom of the vacuum foot is preferably formed by a plurality of mouths 6. An elongated slot 7, as shown in Fig. 5, will, however, have substantially the same effect as a series of holes. The terms air inlet or air intake as herein employed, are, therefore, intended to include a construction in which a single opening is employed, or a construction in which such opening is broken up into a, number of separate mouths by intermediate partitions. The length of the foot 4 is substantially the width of the pile of sheets so that the air inlet at the ends of the foot may act close to the edges of the sheet.

While the vacuum foot may be formed as a single foot of the proper width of one width of the sheets, it may also be made in sections and adjustable for different widths of sheets. Other variations in the structure of the foot may also be made.

While the preferred embodiment of the invention has been illustrated and described, it is to be understood however, that the invention is not limited to its preferred embodiment, but it may be embodied in other constructions of sheet feeding machines within the scope of the following claims.

I claim:

1. A sheet feeding machine, comprising a vacuum sheet lifting foot having an air inlet in its sheet engaging face and having the middle of the sheet engaging face substantially flat but having both ends of the sheet engaging face curved upwardly so as to curl up the edges only of the engaged sheet; substantially as described.

2. A sheet feeding machine, comprising a vacuum sheet lifting foot having a. rigid sheet engaging face substantially fiat at its middle portion and upwardly curved at its ends, said sheet engagingface having an air inlet in the substantially fiat niiddie portion and in the upwardly curving ends, so as to first suctionally engage the middle of the sheet and thereafter to s tionaity engage and curl up the edges oi he sheet; substantially as descril'x-zd.

3. A sheet feeding machine, comprising a vacuum sheet lifting foot having a substantially fiat middle portion and upwardly curved ends, the curved ends merging on a gradual curve with the flat middle portion of the face, and an ai" inlet extending from the flat middle portion and along the curved end portions and operating to first draw the middle portion of the paper against the flat portion of the'foot and thereafter to lift the sheet against the foot progressively upwardly alon the cum ed end portions so as to curl up t e edges only of the sheet and cause a fanning of the edges of the paper; substantially as described.-

In testimony whereof, I have hereunto set my hand.

CARL W. KRUEGER. 

